P0168
Fuel Temperature Too High
If your vehicle's onboard computer has flagged the diagnostic trouble code P0168, it refers to a detected anomaly regarding "Fuel Temperature Too High". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
P0168 is triggered when the PCM detects an abnormal condition associated with fuel temperature too high. The most common signs are vapor lock symptoms, engine stalling when hot, check engine light. This is a moderate-severity fault — plan a repair shop visit within the week to keep it from escalating.
Symptoms
Vapor lock symptoms, engine stalling when hot, check engine light
Common Causes
- Low fuel level in tank (fuel is used to cool the pump)
- Faulty fuel cooler (if equipped)
- Failed fuel temperature sensor
- Fuel lines routed too close to exhaust
How to Fix
- 1 Keep fuel tank at least 1/4 full
- 2 Inspect and repair fuel cooler circuit
- 3 Replace fuel temperature sensor
- 4 Install heat shielding on fuel lines
Technical Explanation
P0168 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. The diagnostic runs during closed-loop operation only, ensuring the engine is at full operating temperature and the PCM's fuel trim feedback loop is active before confirming any out-of-range condition. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
While the vehicle is typically drivable with P0168 active, avoid towing, aggressive acceleration, or extended highway driving until the fault is resolved. The primary risk is accelerated wear on low fuel level in tank (fuel is used to cool the pump) and faulty fuel cooler (if equipped).
Mechanic's Pro Tip
The most common mistake with P0168 is replacing the sensor without verifying the reference voltage and ground integrity first. Use a scan tool to monitor the sensor's live output; a truly failed sensor shows a stuck, flatlined reading — a sensor that fluctuates but reads slightly off usually indicates a wiring or vacuum issue, not a dead sensor. Always spray electrical contact cleaner on the connector pins before condemning the sensor.
Sensor replacement: 100 - 250; Heat shielding: 50 - 100